Note: Descriptions are shown in the official language in which they were submitted.
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VIBRATORY SEPARATOR MOTION
BACKGROUND
Field of the Disclosure
[0001] Embodiments disclosed herein relate generally to apparatuses and
methods for
separating solids from liquids. Specifically, embodiments disclosed herein
relate to
apparatuses and methods for separating solids from liquids using dual motion
profiles
on vibratory separators. More specifically still, embodiments disclosed herein
relate
to apparatuses and methods for producing a first elliptical motion and a
second
elliptical motion on vibratory separators.
Background Art
[0002] Oilfield drilling fluid, often called "mud," serves multiple
purposes in the
industry. Among its many functions, the drilling mud acts as a lubricant to
cool
rotary drill bits and facilitate faster cutting rates. Typically, the mud is
mixed at the
surface and pumped downhole at high pressure to the drill bit through a bore
of the
drillstring. Once the mud reaches the drill bit, it exits through various
nozzles and
ports where it lubricates and cools the drill bit. After exiting through the
nozzles, the
"spent" fluid returns to the surface through an annulus formed between the
drillstring
and the drilled wellbore.
[0003] Furthermore, drilling mud provides a column of hydrostatic
pressure, or head,
to prevent "blow out" of the well being drilled. This hydrostatic pressure
offsets
formation pressures, thereby preventing fluids from blowing out if pressurized
deposits in the formation are breeched. Two factors contributing to the
hydrostatic
pressure of the drilling mud column are the height (or depth) of the column
(i.e., the
vertical distance from the surface to the bottom of the wellbore) itself and
the density
(or its inverse, specific gravity) of the fluid used. Depending on the type
and
construction of the formation to be drilled, various weighting and lubrication
agents
are mixed into the drilling mud to obtain the right mixture. Typically,
drilling mud
weight is reported in "pounds," short for pounds per gallon. Generally,
increasing the
amount of weighting agent solute dissolved in the mud base will create a
heavier
drilling mud. Drilling mud that is too light may not protect the formation
from blow
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outs, and drilling mud that is too heavy may over invade the formation.
Therefore,
much time and consideration is spent to ensure the mud mixture is optimal.
Because
the mud evaluation and mixture process is time consuming and expensive,
drillers and
service companies prefer to reclaim the returned drilling mud and recycle it
for
continued use.
[0004] Another significant purpose of the drilling mud is to carry the
cuttings away
from the drill bit at the bottom of the borehole to the surface. As a drill
bit pulverizes
or scrapes the rock fonnation at the bottom of the borehole, small pieces of
solid
material are left behind. The drilling fluid exiting the nozzles at the bit
acts to stir-up
and carry the solid particles of rock and formation to the surface within the
annulus
between the drillstring and the borehole. Therefore, the fluid exiting the
borehole
from the annulus is a slurry of formation cuttings in drilling mud. Before the
mud can
be recycled and re-pumped down through nozzles of the drill bit, the cutting
particulates must be removed.
[0005] Apparatus in use today to remove cuttings and other solid
particulates from
drilling fluid are commonly referred to in the industry as "shale shakers." A
shale
shaker, also known as a vibratory separator, is a vibrating sieve-like table
upon which
returning solids laden drilling fluid is deposited and through which clean
drilling fluid
emerges. Typically, the shale shaker is an angled table with a generally
perforated
filter screen bottom. Returning drilling fluid is deposited at the feed end of
the shale
shaker. As the drilling fluid travels down the length of the vibrating table,
the fluid
falls through the perforations to a reservoir below leaving the solid
particulate
material behind. The vibrating action of the shale shaker table conveys solid
particles
left behind until they fall off the discharge end of the shaker table. The
above
described apparatus is illustrative of one type of shale shaker known to those
of
ordinary skill in the art. In alternate shale shakers, the top edge of the
shaker may be
relatively closer to the ground than the lower end. In such shale shakers, the
angle of
inclination may require the movement of particulates in a generally upward
direction.
In still other shale shakers, the table may not be angled, thus the vibrating
action of
the shaker alone may enable particle/fluid separation. Regardless, table
inclination
and/or design variations of existing shale shakers should not be considered a
limitation of the present disclosure.
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[0006] Preferably, the amount of vibration and the angle of
inclination of the shale
shaker table are adjustable to accommodate various drilling fluid flow rates
and
particulate percentages in the drilling fluid. Mier the fluid passes through
the
perforated bottom of the shale shaker, it can either return to service in the
borehole
immediately, be stored for measurement and evaluation, or pass through an
additional
piece of equipment (e.g., a drying shaker, centrifuge, or a smaller sized
shale shaker)
to further remove smaller cuttings.
10007] Currently, when a drilling operator chooses a separatory
profile, therein
selecting a type of motion that actuators of the vibratory separator will
provide to the
screen assemblies, they typically choose between a profile that either
processes
drilling material quickly or thoroughly. By increasing the speed of
conveyance, linear
motion vibratory shakers provide increased shaker fluid capacity and increased
processing volume. However, in certain separatory operations, the weight of
solids
may still restrict the speed that linear motion separation provides.
Additionally, while
increased 0-forces enable faster conveyance, as the speed of conveyance
increases,
there is a potential that the produced drilled solids may still be saturated
in drilling
fluid.
[0008] Alternatively, a drilling operator may select a vibratory
profile that imparts
lower force vibrations onto the drilling material, thereby resulting in drier
cuttings and
increased drilling fluid recovery. However, such lower force vibrations
generally
slow drilling material processing, thereby increasing the time and cost
associated with
processing drilling material.
[0009] Accordingly, there exists a need for a vibratory shaker that
produces drier
cuttings and increases drilling fluid recovery while increasing processing
time.
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SUMMARY OF THE DISCLOSURE
100101 In one aspect, embodiments disclosed herein relate to a
vibratory separator
comprising: a first actuator with at least one unbalanced weight coupled to
the basket; a
second actuator with at least one unbalanced weight coupled to the basket; and
a motion
control switch operatively connected to at least one of the first and second
actuators and
configured to modulate motion generated by the first and second actuators
between a first
elliptical motion and a second elliptical motion, wherein one of the first and
second elliptical
motions comprises at least one of a first progressive shape, wherein an aspect
ratio of the first
progressive shape decreases from a feed end of the vibratory separator to a
discharge end of
the vibratory separator, and a second progressive shape, wherein the aspect
ratio of the second
progressive shape decreases from the discharge end of the vibratory separator
to the feed end
of the vibratory separator.
[0011] In another aspect, embodiments disclosed herein relate to a
method of
processing drilling waste, the method comprising: flowing drilling waste over
a screen of a
vibratory separator; imparting a first elliptical motion with a first actuator
with at least one
unbalanced weight to the screen; monitoring the flow of drilling waste over
the screen;
determining an overload condition exists; and adjusting, with a motion control
switch, the
motion to a second elliptical motion with a second actuator with at least one
unbalanced
weight based on the determined load condition, wherein one of the first and
second elliptical
motions comprises at least one of a first progressive shape, wherein an aspect
ratio of the first
progressive shape decreases from a feed end of the vibratory separator to a
discharge end of
the vibratory separator and a second progressive shape, wherein the aspect
ratio of the second
progressive shape decreases from the discharge end of the vibratory separator
to the feed end
of the vibratory separator.
[0012] Other aspects and advantages of the invention will be apparent from
the
following description and the appended claims.
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BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure I is an isometric view of a vibratory separator in
accordance with an
embodiment of the present disclosure.
[0014] Figure 2 is a top view of a vibratory separator in accordance
with an
embodiment of the present disclosure.
[0015] Figure 3 is a side view of a vibratory separator in accordance
with an
embodiment of the present disclosure.
[0016] Figure 4A is a front view of a vibratory separator in
accordance with an
embodiment of the present disclosure.
with an embodiment of the present disclosure.
[0018] Figure 5 is a schematic view of actuators imparting a
substantially balanced
elliptical motion in accordance with an embodiment of the present disclosure.
[0019] Figure 6 is a schematic view of a resultant motion in
accordance with an
[0020] Figures 7A and 7B are schematic views of a motion control
switch in
accordance with an embodiment of the present disclosure.
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[0021] Figures 7C and 7D are isometric views of swing weights in
accordance with
embodiments of the present disclosure.
[0022] Figure 7D is a close perspective view of an actuator in accordance
with an
embodiment of the present disclosure.
[0023] Figure 7E is a side view of a vibratory separator in accordance
with an
embodiment of the present disclosure.
[0024] Figure 7F and 7G are isometric views of swings weights in
accordance with
embodiments of the present disclosure.
[0025] Figure 8 is a schematic view of actuators imparting a progressive
elliptical
motion in accordance with an embodiment of the present disclosure.
[0026] Figure 9 is a schematic view of a resultant motion in accordance
with an
embodiment of the present disclosure.
DETAILED DESCRIPTION
[0027] Generally, embodiments disclosed herein relate to apparatuses and
methods
for separating solids from liquids. Specifically, embodiments disclosed herein
relate
to apparatuses and methods for separating solids from liquids using dual
motion
profiles on vibratory separators. More specifically still, embodiments
disclosed
herein relate to apparatuses and methods for producing a first elliptical
motion and a
second elliptical motion on vibratory separators.
[0028] Traditionally, vibratory separators have been designed to produce a
specific
type of motion, for example, linear, circular, unbalanced elliptical, or
balanced
elliptical. The type of motion was dictated by the placement of actuators
relative to
the vibratory separator body, and as such, the shape of the motion could only
be
changed by physically altering the configuration/placement of the actuators.
Typically, vibratory separators capable of generating a single type of motion
use one
or two motors positioned at a specific location on the shaker body. For
example,
round motion may be generated by a single actuator located proximate the
center of
gravity of the vibratory separator. Linear motion may be generated through the
use of
two counter rotated actuators disposed on the vibratory separator. Multi-
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elliptical motion may be generated with one actuator disposed a select
distance from
the center of gravity of the vibratory separator.
[0029] More recently, complex motion types, such as balanced elliptical
motion, have
been employed through the use of two counter rotated motors disposed on the
vibratory separator. Furthermore, certain vibratory separators are now
designed to
allow for the switching of motion types, such as the switching between linear
and
balanced elliptical motion. Such dual motion vibratory separators typically
use three
or more motors, wherein two motors are used to produce a first motion type,
while the
additional motor or motors are only used to switch to a third motion type. In
alternate
designs, dual motion separators have been designed using two motors, wherein a
physical alternation of the placement of one of the motors allows for a change
in the
motion type or shape.
100301 Embodiments of the present disclosure allow for a two-actuator
separator to
generate at least two motion types, such as a substantially balanced
elliptical motion
and an unbalanced, or progressive, elliptical motion. Substantially balanced
elliptical
motion, as used herein, refers to an elliptical motion that remains
substantially
constant across a screen, so that cuttings processed at a feed end of a
separator are
exposed to substantially the same motion type as cuttings processed at a
discharge end
of the separator. Those of ordinary skill in the art will appreciate that a
substantially
balanced elliptical motion may further refer to a motion shape that has an
aspect ratio
that varies less than 30% throughout the length of the vibratory separator. In
certain
aspects, substantially balanced elliptical motion may refer to a motion shape
that has
an aspect ratio that varies less than 20% or less than 10% throughout the
length of the
vibratory separator. Those of ordinary skill in the art will further
appreciate that
modulating the type of motion depending on operational parameters of the
drilling
operations, such as drill cutting flow rate, may allow for a more efficient
processing
of drilled solids. Balanced elliptical motion allows for a relatively fast
processing of
drilled solids while preserving screen life compared to linear motion of equal
acceleration. In contrast, progressive elliptical motion allows for cuttings
to be
quickly transferred off of a feed end of a vibratory separator, while allowing
the
cuttings to be retained at a discharge end longer, thereby resulting in
relatively drier
cuttings. In certain embodiments, a first elliptical motion, such as a
balanced
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elliptical motion, may have a relatively high aspect ratio that results in
relatively fast
cuttings transferences, while a second elliptical motion, such as a
progressive
elliptical motion, may have a relatively low aspect ratio that results in
relatively slow
cuttings transference. Those of ordinary skill in the art will appreciate that
generally,
the wider the aspect ratio of the ellipse, the slower cuttings are discharged
from the
vibratory separator. For example, ellipse aspect ratios of greater than 3/1
may
generally result in fast cuttings transference, while ellipse aspect ratios of
less than 3/1
may result in relatively slow cuttings transference. While specific
embodiments of
the present disclosure will be discussed in detail below, generally,
embodiments
disclosed herein may allow for the modulation between motion types and or
shapes by
changing the operational parameters of a vibratory separator.
[0031] Referring initially to Figures 1-4A, isometric, top, side and front
views of a
vibratory separator 100 in accordance with an embodiment of the present
disclosure
are shown. In this embodiment, vibratory separator 100 includes a frame 101,
side
walls 102, a discharge end 103, and an inlet end 104. Vibratory separator 100
also
includes a basket 105 that holds a screen assembly 106. Operationally, as
drilling
material enters vibratory separator 100 through inlet end 104, the drilling
material is
moved along screen assembly 106 by a vibratory motion. As screen assembly 106
vibrates, residual drilling fluid and particulate matter may fall through
screen
assembly 106 for collection and recycling, while larger solids are discharged
from
discharge end 103.
[0032] In one embodiment, vibratory motion is supplied by a plurality of
actuators
107a and 107b coupled to a support member 108 for imparting the vibratory
motion to
basket 105. Actuators 107 are driven by rotary motors (not shown) having
shafts (not
shown) coupled to identical unbalanced weights (not shown) attached to
opposite
ends of the shafts. Those of ordinary skill in the art will appreciate that
the weights
may be substantially identical on each individual motor, while the weights may
not be
identical on separate motors.
[0033] A motion control switch (not independently illustrated) is also
operatively
connected to actuators 107 to allow for the switching between a plurality of
motion
types and shapes. In one embodiment, motion control switch may include a
mechanical switch to allow an operator to select between at least two modes of
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operation, for example, to select between a progressive elliptical motion and
a
balanced elliptical motion. In other embodiments, the motion control switch
may
include a user interface, such as a digital control interface, to allow an
operator to
select between motion types, shapes, or control specific operational
parameters, such
as, for example, actuator force output or actuator speed. In certain
embodiments,
vibratory separator 100 may include multiple motion control switches
operatively
connected to one or more of actuators 107, thereby allowing for the switches
to be
modulated individually or together to allow for the switching between a
plurality of
motion types and shapes.
[0034] In certain embodiments the rotary motors may be operatively
connected to a
programmable logic controller ("PLC") (not shown) that may supply instructions
to
actuators 107 or other components of vibratory separator 100. The instructions
to
actuators 107 may include vibratory motion protocols that define a pattern of
movement for moving basket 105. In other embodiments, the motion control
switch
and/or PLC may include instructions to modulate a power signal to at least one
of
actuators 107a and 107b. By changing the power signal, actuators 107a and 107b
may operate at a selected speed, thereby changing the resultant acceleration
of the
motion.
[0035] While both actuators 107a or 107b operate at the same speed,
embodiments
disclosed herein include actuators 107a and 107b that have eccentric weights
that
swing in different directions depending on whether the rotation of the weights
are in a
forward direction or a reversed direction. Thus, by modulating the rotation of
the
weights from a forward direction to a reverse direction, the shape of the
motion
imparted to basket 105 may be changed. Those of ordinary skill in the art will
appreciate that design parameters of vibratory separators that may change a
resultant
motion produced include the force ratio of each actuator, the distance between
the
actuators, the angle of a platfomi relative to the screens, mass and inertia
properties of
the baskets, the angle of a mounting surface relative to the basket, and the
placement
of the actuators relative to the center of gravity of the separator.
[0036] PLCs may be used to control the resultant motion by, for example,
instructing
a variable frequency drive to slow or reverse the direction of rotation of the
eccentric
weights of one or more of actuators 107a and 107b. In other embodiments, the
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operation of actuators 107a and/or 107b may be controlled directly through a
vibratory separator control system. Those of ordinary skill in the art will
appreciate
that PLCs are not a requirement for all applications, and as such, actuators
may be
independently controllable with or without a PLC. In certain embodiments, the
motion control switch may send instructions though a PLC, or a motion control
switch
and a PLC may function together as part of a user interface.
[0037] Referring now to Figure 4B, a schematic view of a rotational
motion of
actuators during operation of a vibratory separator in accordance with one
embodiment of the present disclosure is shown. In this embodiment, the
instructions
from the PLC to the motors may define a pattern of movement that constitutes a
desired motion type. In such an embodiment, the motors may drive actuators
107a
and 107b thereby rotating unbalanced weights 509b and 509a in opposite
directions
510b and 510a around their respective axes of rotation 511b and 511a. The
rotation
of unbalanced weights 509b and 509a produces centrifugal forces 512b and 512a
as
the centers of mass 513b and 513a rotate in equal planes relative to their
respective
axes of rotation 511b and 511a.
[0038] Referring to Figure 5, a schematic view of actuators imparting a
balanced
elliptical motion, according to embodiments of the present disclosure, is
shown. In
this embodiment, a first actuator 501 and a second actuator 502 are
illustrated,
wherein each actuator 501 and 502 have respective shafts 503 and 504 upon
which
unbalanced weights 505 and 506 rotate. As illustrated, actuators 501 and 502
are
configured such that unbalanced weights 505 and 506 rotate as represented by
directional arrows A and B. During such rotation, unbalanced weight 505
rotates in
direction A, while unbalanced weight 506 rotates in direction B. Unbalanced
weights
505 and 506 may or may not be equal weights, and as such, may include
different
sizes, depending on the particular type of motion being generated.
[0039] Referring to Figure 6, a schematic view of a resultant motion of a
vibratory
separator 600 according to embodiments of the present disclosure is shown. In
this
embodiment, actuators 601 and 602, similar to actuators 501 and 502 of Figure
5, are
shown. In this embodiment, vibratory separator 600 includes a screening deck
603
and a flow of drilled solids 604 passing thereacross. The rotation of
unbalanced
weights (not illustrated) of actuators 601 and 602 rotating generates a thin-
ellipse
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shaped resultant motion 605, which is substantially similar along the length
of
screening deck 603. In this embodiment, the force output of actuator 601 is
larger
than the force output of actuator 602. For example, the force output of
actuator 601
may be in a range between 1.0 and 1.5 times the force output of actuator 602.
In
certain embodiments, the force output of actuator 601 may be, for example, 1.2
times
the force output of actuator 602.
[0040] As illustrated, the angle of acceleration (shown as reference
character 606) of
the motion is approximately 45 relative to screen deck 603. A 45 angle of
acceleration 606 may allow for an optimal transference of drilled solids
across screen
deck 603 by providing adequate energy to separate liquid phase from the solids
phase,
while also transferring the drilled solids across screen deck 603 efficiently.
However,
in alternate embodiments, angle of acceleration 606 may vary between for
example
30 and 60 , and in certain embodiments may be greater than 60 or less than
30 .
Those of ordinary skill in the art will appreciate that the angle of
acceleration 606 and
the aspect ratio of the resultant ellipse may be varied to optimize the
resultant
balanced elliptical motion.
100411 In this embodiment, the thin-ellipse has a relatively longer major
axis to minor
axis, and as such, those of ordinary skill in the art will appreciate that
balanced
elliptical motion may allow for a relatively fast transference of drilled
solids across
screen deck 603. Accordingly, balanced elliptical motion may be beneficial to
use
when the drilling operation is producing a high flow rate of drilled solids to
vibratory
separator 600. Additionally, in contrast to other types of motion, such as
linear
motion, balanced elliptical motion may result in longer screen life. Unlike
linear
motion, which results in a full stop at each end of the stroke, elliptical
motion is
continuous, thereby reducing the impact by the material against the screen.
Finally,
balanced elliptical motion results in a tumbling of drilled solids across the
screens,
thereby providing increased separation of liquid phase from solid phase.
[0042] Referring to Figures 7A and 7B together, schematic illustrations of
a motion
control switch 707 according to embodiments of the present disclosure are
shown. In
a first embodiment represented at Figure 7A, actuators 701 and 702 are
operatively
coupled to motion control switch 707. Motion control switch 707 is configured
to
control the type of motion generated by actuators, and as such, may contain
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instructions or control logic for operating actuators 701 and/or 702 to
produce a
desired force output and therefore a desired type of motion. Those of ordinary
skill in
the art will appreciate that modifying other design parameters of vibratory
separators
may also change the type of motion generated. In this embodiment, motion
control
switch 707 is configured to modulate the force output of actuators 701 and
702, and
also control the direction of rotation of unbalanced weights. Figure 7A
illustrates a
configuration of actuators 701 and 702 and motion control switch 707 that
generates
balanced elliptical motion, as described above. In this embodiment, motion
control
switch 707 provides instructions to actuators 701 and 702 instructing
actuators 701
and 702 to rotate as illustrated. Additionally, motion control switch 707
provides
instructions to control the force output of actuators 701 and 702, which in
this
embodiment, includes instructions for 100% force output from each motor.
However,
in alternate embodiments, the force output may be kept relatively equal.
[0043] As illustrated, F1 defines the force output of actuator 701, while
F2 defines the
force output of actuator 702. In this embodiment, the force output of actuator
701 is
larger than the force output of actuator 702. For example, the force output of
actuator
701 may be in a range between 1.0 and 1.5 times the force output of actuator
702. In
certain embodiments, the force output of actuator 701 may be, for example, 1.2
times
the force output of actuator 702. Those of ordinary skill in the art will
appreciate that
a particular range of force ratios may vary based on a desired motion shape
and/or
other design parameters, such as, for example, the location of actuators 701
and 702
relative to the center of gravity of a vibratory separator 700, the spacing
between
actuators 701 and 702, the angle formed between an actuator mounting surface
and
the basket of vibratory separator 700, mass and inertia properties of
vibratory
separator 700, and a rotational speed of one or more of actuators 701 and 702.
Referring briefly to Figure 7E, a side view of a vibratory separator 700
according to
embodiments of the present disclosure is shown. As illustrated, actuators 701
and 702
are mounted on vibratory separator 700 at a particular mounting angle 0.
Mounting
angle may vary depending on the mounting location of actuators 701 and 702
relative to a top screen surface of vibratory separator 700. By adjusting
mounting
angle 0, a motion shape of vibratory separator 700 may be varied, so as to
optimize a
particular motion shape used in the processing of drill cuttings. In certain
embodiments, mounting angle may range between substantially 00 to about 450
,
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while in other embodiments, mounting angle Co may range between about 100 and
about 30 .
[0044] Referring back to Figure 7A, motion control switch 707 may be an
independent component of a vibratory separator, such as a PLC, as discussed
above.
In such an embodiment, an operator may selectively control the operation of
the
vibratory separator by, for example, turning a physical switch or programming
new
instructions into a digital user interface. In other embodiments, motion
control switch
707 may include a component of a vibratory separator operation system, and as
such,
may include hardware and/or software components. Accordingly, in certain
embodiments, selecting an operation mode for a vibratory separator may include
use
of a motion control switch to instruct the actuators independently or through
the use
of a vibrator control system to generate a specific type of motion. In this
embodiment, an operator may program a vibratory separator to generate balanced
elliptical motion (or progressive elliptical motion), or alternatively, an
operator may
program a vibratory separator to operate in a high gravity-force mode or a
screen life
mode. In still other embodiments, motion control switch 707 may operate as
part of
an automated control system to determine changes in the flow rate of cuttings
into the
separator, thereby automatically adjusting the motion type generated.
[0045] Figure 7B illustrates a second mode of operation for a vibratory
separator, in
which the operations of actuators 701 and 702 have been modified by motion
control
switch 707. In this embodiment, motion control switch 707 instructed actuators
701
and 702 to reverse the direction of rotation of unbalanced weights 708 of
actuators
701 and 702. As such, the rotation of unbalanced weights 708 results in a
progressive
elliptical motion. While progressive elliptical motion will be explained in
detail
below, those of ordinary skill in the art will appreciate that switching
between
substantially balanced elliptical motion and progressive elliptical motion may
allow
an operator to adjust the type of motion generated by a vibratory separator to
match a
condition of the drilling operation. As such, the efficiency of the operation
may be
increased without increasing the number of physical components at a drilling
location.
[0046] As illustrated, F 1 defines the force output of actuator 701, while
F2 defines the
force output of actuator 702. In this embodiment, the force output of actuator
701 is
larger than the force output of actuator 702. For example, the force output of
actuator
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701 may be in a range between 1.5 and 2.0 times the force output of actuator
702. In
certain embodiments, the force output of actuator 701 may be, for example,
1.66
times the force output of actuator 702. Those of ordinary skill in the art
will
appreciate that a particular range of force ratios may vary based on a desired
motion
shape and/or other design parameters, such as, for example, the location of
actuators
701 and 702 relative to the center of gravity of a vibratory separator 700,
the spacing
between actuators 701 and 702, the angle formed between an actuator mounting
surface and the basket of vibratory separator 700, mass and inertia properties
of
vibratory separator 700, and a rotational speed of one or more of actuators
701 and
702.
[0047] Referring to Figures 7C and 7D, isometric views of swing weights
according
to embodiments of the present disclose are shown. Figure 7C illustrates swing
weights including an inner weight 708B and an outer weight 708A. In this
embodiment, outer weight 708A is fixed to actuator shaft 711, while arcuate
member
714 is attached to inner weight 708B. Arcuate member 714 include two stops
713A
and 713B, which are configured to contact inner and outer weights 708B and
708A
during operation. During operation, as outer weight 708A is rotated counter-
clockwise, in direction C, outer weight 708A contacts stop 713A. As stop
arcuate
member 714 is attached to inner weight 708B, the contact of outer weight 708A
with
stop 713A causes inner weight 708B to be driven with outer weight 708A in
direction
C. Such a configuration results in a relatively high unbalance, which may be
used to
generate a substantially balanced elliptical motion.
[0048] Referring to Figure 7D, swing weights include an inner weight 708B
and an
outer weight 708A. In this embodiment, outer weight 708A is rotated on
actuator
shaft 711 clockwise, in direction D. As outer weight 708A rotates, it contacts
stop
713B, which drives inner weight 708B with outer weight 708A in direction D.
Such a
configuration results in a relative low unbalance value, and may be used to
generate a
progressive elliptical motion.
[0049] Referring back to 7B, actuators 701 and 702 may be rotated toward
each other
while producing a relatively out-of-balance force output ratio, thereby
resulting in a
progressive elliptical motion. In contrast, referring back to Figure 7A,
actuators 701
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and 702 may be rotated away from each producing a relatively similar force
output
ratio, thereby resulting in a balanced elliptical motion.
100501 Referring to Figures 7F and 7G, isometric views of swing weights
according
to embodiments of the present disclose are shown. Referring initially to
Figure 7F, a
first position of swing weights 708A and 708B are shown. In this embodiment,
inside
weight 708B is fixed to an actuator shaft 711 of the actuator, while outside
weight
708A is free to rotate. As illustrated, swings weights 708A and 708B are shown
with
100% unbalance, or a relatively high unbalance, which may be used to provide a
motion type illustrated in Figure 6, and schematically illustrated in Figure
7A. In this
embodiment, a pin 710 that is disposed on outside weight 708A fits into a slot
(not
shown) of inside weight 708B. When inside weight rotates clockwise, in
direction A,
pin 710 bottoms out in the right side of the slot of inner weight 708B,
thereby causing
a relatively high unbalance. Referring to Figure 7G, a second position of
swing
weights 708A and 708B is shown. In the second configuration, swing weights
708A
and 708B as illustrated wherein inside weight 708B includes a slot 712, while
outside
weight 708A includes a pin 710. When rotating the inside weight counter-
clockwise,
indicated as direction B, pin 710 of outer weight 708A bottoms out in the left
side of
slot 712 of inner weight 708B, thereby causing a relatively low unbalance.
Such a
configuration may be used to provide a progressive elliptical motion shape,
such as
the shape that is described in greater detail in Figure 9, below.
100511 By adjusting the relative positions of swing weights 708A and
708B, the type
of motion produced may be varied. For example, in certain embodiments, a
resulting
acceleration of the first elliptical motion may be less than a resulting
acceleration of
the second elliptical motion. In particular embodiments, the resulting
acceleration of
the first elliptical motion may be in a range of about 60% to about 95% of the
acceleration of the second elliptical motion. In other embodiments, a
resulting
displacement of the first elliptical motion may be less than a resulting
displacement of
the second elliptical motion. In such an embodiment, the first and second
elliptical
motion profiles may have a substantially similar shape, with a different
stroke length,
which may thereby result in different conveyance speeds. Such an embodiment
may
thereby adjust the motion profiles while maintaining a substantially constant
acceleration for both profiles. In particular embodiments, the resulting
displacement
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of the first elliptical motion may be in a range of about 10% to about 95% of
the
displacement of the second elliptical motion. In such an embodiment, the
motion may
be modulated by changing a rotational speed of one or more of the first and
second
actuators. Additionally, to modulate a force output of one or more of the
first and
second actuators, at least one of the first and second actuators may include a
swing
weight, as described above.
100521 Referring to Figure 8, a schematic view of actuators imparting a
progressive
elliptical motion, according to embodiments of the present disclosure is
shown. In
this embodiment, a first actuator 801 and a second actuator 802 are
illustrated,
wherein each actuator 801 and 802 have respective shafts 803 and 804 upon
which
unbalanced weights 805 and 806 rotate. As illustrated, actuators 801 and 802
are
configured such that unbalanced weights 805 and 806 rotate as represented by
directional arrows A and B. During such rotation, unbalanced weight 805
rotates in
direction A, while unbalanced weight 806 rotates in direction B.
[0053] Referring to Figure 9, a schematic view of a resultant motion to a
vibratory
separator 900 according to embodiments of the present disclosure is shown. In
this
embodiment, vibratory separator 900 includes a screening deck 903 and a flow
of
drilled solids 904 passing thereacross from a feed end 906 to a discharge end
907.
The rotation of unbalanced weights (not illustrated) of actuators 901 and 902
rotating
generates a resultant motion 905 that varies across screening deck 903. In
this
embodiment, the force output of actuator 901 is larger than the force output
of
actuator 902. For example, the force output of actuator 901 may be in a range
between 1.5 and 2.0 times the force output of actuator 902. In certain
embodiments,
the force output of actuator 901 may be, for example, 1.66 times the force
output of
actuator 902.
[0054] Progressive elliptical motion includes the formation of different
aspect ratio
ellipses along the length of screening deck 903. For example, in this
embodiment,
resultant motion 905A at feed end 906 includes a relatively thin ellipse
having a
longer major axis relative to a minor axis. Resultant motion 905A may thereby
result
in an ellipse similar to that typically produced during balanced elliptical
motion, as
described above. As drilled solids flow across screening deck 903, the aspect
ratio of
the ellipse of the resultant motion 905 changes. For example, resultant motion
905B
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includes a relatively wider ellipse. Still further, as drilled solids progress
across
screening deck 903 toward discharge end 907, resultant motion 905C may
approximate round or circular motion. Resultant motion 905C may thereby cause
drilled solids to tumble more slowly than motion 905B. Accordingly, drilled
solids
may be retained on screening deck 903 for a longer period of time, thereby
resulting
in drier discharged cuttings.
[0055] Those of ordinary skill in the art will appreciate that progressive
elliptical
motion may provide the benefits of both round and linear motion. For example,
the
thin aspect ellipse (i.e., high aspect ellipse) at feed end 906 may increase
the speed at
which drilled solids are transferred across screening decking 903. However, as
the
drilled solids progress across screening deck 903, the wider aspect ellipses
(i.e., low
aspect ellipse) slow the progression of the drilled solids, such that drilled
solids may
be retained on the screening deck 903 longer. By increasing the time the
drilled solids
remain on screening deck 903, relatively drier drilled solids may be produced.
[0056] Progressive elliptical motion may thereby provide ellipses of
different aspect
ratios across the screen of a vibratory separator. For example, in one
embodiment, a
progressive elliptical motion may result in an aspect ratio that decreases
when moving
from a feed end of the vibratory separator to a discharge end of the vibratory
separator. In certain embodiments, the aspect ratio of the progressive
elliptical
motion may decrease about 30% or greater from the feed end to the discharge
end. In
other embodiments, the aspect ratio of the progressive elliptical motion may
decrease
between 50% to over 1000% from the feed end to the discharge end. In other
embodiments, a progressive elliptical motion may result in an aspect ratio
that
decreases when moving from the discharge end to the feed end. In such an
embodiment, the aspect ration of the progressive elliptical motion may
decrease about
30% or greater from the discharge end to the feed end. In other embodiments,
the
aspect ratio of the progressive elliptical motion may decrease between 50% to
over
1000% from the he discharge end to the feed end. Depending on the particular
location on the screen of a vibratory separator, the aspect ratio of an
ellipse may range
between 1.5 and 20Ø Thus, an aspect ratio of an ellipse or a progression of
ellipses
across the screen of a vibratory separator may be varied to balance the
requirements to
produce dry cuttings while maintaining a desired processing speed.
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[0057] Those of ordinary skill in the art will appreciate that in
alternate embodiments,
additional actuators may be used to impart additional motion types to the
basket
and/or the frame of the separator. For example, a third actuator may be
operatively
coupled to the motion control switch, thereby allowing additional vibratory
motions to
be generated. In still other embodiments, additional components, such as
sensors,
control units, and reluctance motors, may be used to change aspects of
vibratory
separator operation. For example, in certain embodiments, reluctance motors
may be
used to synchronize the motion of the actuators during balanced elliptical
motion,
sensors may be used to measure the resultant motion being produced, and
control
units may be used to vary operational parameters, such as actuator force
output.
Additionally, referring briefly back to Figure 7C, bearings 158 disposed
within
actuator 107 may be cylindrical rather than spherical. In the present
disclosure, two
actuators 107 are disposed on horizontal shafts, configured to transmit
vibratory
motion to a basket of the vibratory separatior. Additionally, dual actuators
107 are
configured to produce both a balanced elliptical and progressive elliptical
motion. By
including cylindrical bearings instead of spherical bearings, actuators 107
arranged on
horizontal shafts (as illustrated in Figures 1-4A), may advantageously
withstand
operational conditions, thereby extending the life of actuators 107, and/or
decreasing
the amount of maintenance on actuators 107. Additionally, vibratory separators
having dual actuators 107 disposed on horizontal shafts configured to produce
only a
balanced elliptical or progressive elliptical motion may benefit from the
present
disclosure. Furthermore, other dual motion drive configurations (e.g.,
actuators that
produce both linear and balanced elliptical or both linear and progressive
elliptical)
may benefit from the use of cylindrical bearings. Moreover, in certain
embodiments,
actuators 107 used to produce balanced elliptical and/or progressive
elliptical motion
may not include swinging weights, as discussed above with respect to the
present
disclosure. In such actuators 107 not using swinging weights, cylindrical
bearings
may also be used instead of spherical bearings to further increase the
integrity of
actuator 107. Thus, those of ordinary skill in the art will appreciate that
actuators 107
used to produce vibratory motion for vibratory separators may benefit from the
use of
cylindrical bearings in accordance with the embodiments discussed herein.
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[0058]
During operation, a drilling operator may provide a flow of drilling waste,
including drilled solids, over a screen of a vibratory separator. Initially, a
specific
motion may be imparted to a screening deck, and thus the screen, of the
vibratory
separator. In one embodiment, the initial motion may include a progressive
elliptical
motion. As the vibratory separator imparts the motion to the screen, and thus
moves
drilled solids thereacross, the flow of drilling waste of the screens may be
monitored.
In one embodiment, the monitoring of the drilling waste may include visual
inspection of the progression of the drilled solids across the screens, while
in other
embodiments, sensors on the vibratory separator may monitor the rate of
drilling fluid
flow into the vibratory separator. Examples of sensors may include ultra sonic
sensors and/or other sensors that measure the depth of a fluid pond of a
vibratory
separator. In still other embodiments, the mass of drilling waste on the
vibratory
separator may be determined using sensors, thereby allowing the vibratory
separator
or an operator to determine when an overload condition occurs.
[0059] An
overload condition may be a predetermined flow rate of drilling waste into
vibratory separator, or alternatively, may be a specific mass of drilling
waste on the
screen deck. In still other embodiments, an overload condition may occur if
one side
of the vibratory separator, such as a discharge or feed end, has a mass of
drilling
waste that is too high for efficient processing. After an overload condition
is
determined, the motion of the vibratory separator may be adjusted to, for
example, a
balanced elliptical motion, such that drilling waste is moved across the
screening deck
more quickly. By varying a type of motion produced by a vibratory separator
between a progressive elliptical and balanced elliptical motion, the benefits
of
enhanced drying provided by progressive elliptical and the benefits of faster
processing speeds of balanced elliptical motion may be achieved without the
need for
modifying the physical structure of vibratory separator components.
[0060] In
addition to determining an overload condition, an operator or the vibratory
separator may be configured to determine when a nornial condition occurs. A
normal
condition may include a predetermined drilled solids flow rate, or
alternatively, a
predefined mass of drilling waste on the screening deck. When a normal
condition is
detel ____________________________________________________________________
mined, a vibratory separator operating to generate balanced elliptical motion
may
be adjusted to generate progressive elliptical motion. Thus, upon actuation by
an
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operator, or through automation, vibratory separators according to embodiments
disclosed herein may provide for the adjustment of motion types of match a
specific
drilling and/or or waste return conditions.
[0061] In still other embodiments, operation of a vibratory separator
according to
embodiments disclosed herein may include adjustment of a motion between
specific
modes of operation. For example, in one embodiment, a vibratory separator may
be
programmed to operate in an efficiency mode and a high acceleration mode. As
discussed above, an efficiency mode may include operation using an progressive
elliptical motion, while a high acceleration mode may include operation using
a
balanced elliptical motion. Such operational modes may thereby allow an
operator or
the vibratory separator through automation to determine if the flow or mass of
drilling
waste requires adjustment of the operation mode. If adjustment of the
operation
mode, for example from an efficiency mode, is desired, then an operator or the
vibratory separator may adjust the motion to, for example, a high acceleration
profile.
[00621 While the above embodiments have been described relative to
switching
between two motion profiles, specifically, between a balanced elliptical
motion and a
progressive elliptical motion, those of ordinary skill in the art will
appreciate that
multiple sub- profiles, including balanced or progressive elliptical motion
types, may
also be selected. For example, a vibratory separator may be configured to
produce
multiple aspect ratio ellipses during a single mode of operation. In one
embodiment,
a vibratory separator may be configured to produce a balanced elliptical
motion with
multiple angles of acceleration (e.g., 45 , 500, and 55 ). Thus, an operator
may also
be able to choose between the angle of acceleration of the balanced elliptical
motion.
Similarly, a vibratory separator may be configured to produce varied
progressive
elliptical motion profiles by, for example, changing the force output from one
or more
of the actuators. In one embodiment, the force output of a first actuator may
be
relatively larger than the force output of a second actuator, such as the
force output of
a first actuator being in a range between 1.5 and 2.0 times the force output
of a second
actuator. By increasing the force output of the second actuator, the resultant
motion
of the screening deck may be change. In other embodiments, by decreasing the
force
output of the first actuator, the resultant motion may also be changed. Thus,
in
addition to allowing selection between a balanced and progressive elliptical
motion,
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embodiments disclosed herein may allow for the selection between sub-motion
types
by varying the relative force output of one or more of the actuators of the
vibratory
separator.
[0063] For example, depending on the particular requirements of a
separatory
operation, the motion may be modulated between a first elliptical motion, such
as a
substantially balanced elliptical motion, and a second elliptical motion, such
as a
progressive elliptical motion. In other embodiments, by varying, for example,
the
relative force output of one or more of the actuators, the motion may be
modulated
between a first elliptical motion, such as a substantially balanced elliptical
motion,
and a second elliptical motion, such as a second substantially balanced
elliptical
motion. In still other embodiments, by varying, for example, the relative
force output
of one or more of the actuators, the motion may be modulated between a first
elliptical motion, such as a progressive elliptical motion, and a second
elliptical
motion, such as a second progressive elliptical motion.
100641 Advantageously, embodiments of the present disclosure may allow for
a more
efficient processing of drilling waste. Because embodiments disclosed herein
allow a
single vibratory separator to modulate between balanced elliptical and
progressive
elliptical motion types, the vibratory separator may process drilling waste
with
increased efficiency. Furthermore, embodiments disclosed herein may allow for
the
generation of both balanced elliptical and progressive elliptical motion
through the
use of two actuators, instead of three or more actuators. By decreasing the
number of
actuators, stress points on the vibratory separator frame may be decreased,
thereby
increasing the integrity of the vibratory separator. Additionally, by
decreasing
components of the vibratory separator, typical maintenance associated with
components of the vibratory separator may also be decreased.
100651 While the present disclosure has been described with respect to a
limited
number of embodiments, those skilled in the art, having benefit of this
disclosure, will
appreciate that other embodiments may be devised which do not depart from the
scope of the disclosure as described herein. Accordingly, the scope of the
disclosure
should be limited only by the attached claims.
